Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual marca tem o indicativo de chamada DXGH?
 ###Tabelas: CREATE TABLE season_to_season (season_to_season_id AUTO_INCREMENT PRIMARY KEY, Season INT, Level VARCHAR, Division VARCHAR, Administration VARCHAR, Position VARCHAR) CREATE TABLE intercounty_connector_bus_routes (intercounty_connector_bus_routes_id AUTO_INCREMENT PRIMARY KEY, Route VARCHAR, Terminus VARCHAR, Operated by VARCHAR, Corridors served VARCHAR, Total trips (AM/PM) VARCHAR, Operating since VARCHAR) CREATE TABLE year-by-year_stats (year-by-year_stats_id AUTO_INCREMENT PRIMARY KEY, Team INT, Games Played INT, Wins INT, Losses INT, Winning Percentage INT, Points For INT, Points Against INT, Point Differential INT) CREATE TABLE grade_distribution (grade_distribution_id AUTO_INCREMENT PRIMARY KEY, Score VARCHAR, 2007 VARCHAR, 2008 VARCHAR, 2009 VARCHAR, 2010 VARCHAR, 2011 VARCHAR, 2012 VARCHAR) CREATE TABLE dzrh_nationwide (dzrh_nationwide_id AUTO_INCREMENT PRIMARY KEY, Branding VARCHAR, Callsign VARCHAR, Frequency VARCHAR, Power (kW) VARCHAR, Station Type VARCHAR, Location VARCHAR)  
SELECT Branding FROM dzrh_nationwide WHERE Callsign = DXGH